Coaxial couplings, particularly those which conduct high and low pressure fluids, are well known in the art. An example of such a coupling is shown in U.S. Pat. No. 6,179,001 B1 to Schutz. This type of coupling assembly permits a rapid-action connection of a male and female coupling that sealingly closes when the male and female halves are disconnected. Typically, these concentric, coaxial coupling are attached with coaxial hose assemblies.
Coaxial hose assemblies are generally used to conduct hydraulic fluid, for example, from a driving element such as a pump, to a hydraulically driven apparatus such as a tool and then return the hydraulic fluid back to a reservoir that supplies the pump with fluid. Typically, the concentric inner passage of both the hose assembly and coaxial coupling is filled with high pressure working fluid, while the outer concentric passage of both the hose assembly and coupling is filled with the low pressure return fluid.
Trapped pressurized fluid or flow impediments are harmful to the coaxial coupling assembly. Connection of the two halves is difficult if the pressure in either half has escalated due to trapped fluid. Sudden pressure surges within the hose assemblies can cause harm to all of the components. Therefore, it is desirable to control the fluid flow through the coupling halves and ensure that trapped pressurized fluid is properly dissipated without harming the assembly.
Coaxial couplings are comprised of a multitude of components. It is necessary to properly seal the areas where connections are made between the components to ensure that pressurized fluid does not escape. In addition, sudden pressure spikes within the assembly can extrude the seals that reside in and between the components.
At some point, due to age, misuse, etc., the conduit that provides the connection to the coaxial coupling halves will have to be replaced. It is cost prohibitive to replace both the conduit and its mating coaxial coupling. Some prior art patent structures combine the coaxial coupling and conduit into an integral assembly. The end fitting that attaches to the conduit is also a primary component of the coupling. Therefore, replacement of the hose assembly, which is comprised of the conduit and attached end fitting, is impractical without replacing the coupling.
Valving componentry is needed for the interconnection of fluid paths. It is desirable to provide an unimpeded connection so that a smooth fluid connection is achieved. Small passageways restrict the fluid flow and interrupt the smooth continuous passage of fluid. It is desirable to have a full passage at the mating halves of the male and female couplings immediately upon the connection. Passageways through the valving components can restrict the fluid flow and provide a hindrance to a smooth continuous flow.
The connector, or port, at the driving component, e.g. the pump, and the driven component, e.g. the tool, can have various configurations. Both twin-line and concentric coaxial connectors are commonly used at the port. Therefore, both mating twin line or concentric coaxial conduits are used. Since it is costly and inconvenient to carry both styles of mating coaxial couplings, it is desirable to have but one coaxial coupling that can mate with both the twin line and coaxial styled conduits.
Coaxial couplings are commonly used in unclean environments, with properly sealed components within the coaxial coupling, preventing outside contaminants from entering. If contaminants do enter, the joints and seals of the mating componentry can be adversely affected. The locking collar assembly of a quick disconnect, coaxial coupling functions with internal springs and locking componentry that are housed within a cavity isolated from outside contaminants. Thus, it is essential that seals between the mating and moving components not only prevent contaminants from entering, but also not hinder necessary movements between the components.
Since both of the male and female halves of the coaxial coupling are concentric, proper mating can only occur if they both remain concentric. Soft connecting joints between the components can allow one component to move radially relative to another, thus causing this coupling half to be eccentric. Strong, secure joints between the components ensure that one coupling half remains concentric and sealingly mates with the other half.
Prior art coaxial coupling have integrated the end fitting of the connecting hose assembly into the componentry of the coaxial coupling. Therefore the same component that is used as a functioning part of the male and/or female coaxial coupling connects with the conduit. Although this design reduces the number of components for the entire coaxial coupling assembly, i.e. the coaxial coupler with the hose assembly, it also eliminates any reusability of the coaxial coupling. For example, if one of the conduits fails during use of the coaxial coupling assembly, it is desirable to change only the failed conduit. This can not be done if the conduit is permanently attached with a component of the coaxial coupling. The entire coaxial coupling assembly has to be replaced in such a case, which adds cost for the enduser.